1. Field of the Invention
This invention relates to an automated mechanical transmission system for use in commercial vehicles, the system for electro-hydraulically automating a combination of a mechanical friction clutch and a mechanical transmission, and more particularly to an automated mechanical transmission system, in which the pressure of clutch disk is directly controlled by pressure oil, the transmission is a counter shaft type, and the oil hydraulic circuit for controlling them is an oil hydraulic feed back type.
2. Description of the Related Art
In the present, pneumatically controlled type automated mechanical transmission systems have been widely used for city bus systems.
In the transmission system, the clutch is an oil-sprayed spring type. The clutch control is a spring chamber type and actuated pneumatically. The transmission is a constant-mesh countershaft type and the transmission control employs the shift and select shaft which is pushed and pulled by a select air cylinder and twisted by a shift air cylinder.
City buses with this system are used by many customers in Japan. Its fuel economy is equal to or slightly better than that of a manual shift transmission.
In city bus use, running smoothness is excellent, while the quickness of response is a little inferior because of the relatively large torque interruption at gear shifting.